From e2eb02480c5407cc918f2dd90ee856bd2e549465 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 22 Feb 2023 09:07:02 -0800 Subject: [PATCH] btrfs: cleanup the main loop in btrfs_lookup_bio_sums Introduce a bio_offset variable for the current offset into the bio instead of recalculating it over and over. Remove the now only used once search_len and sector_offset variables, and reduce the scope for count and cur_disk_bytenr. Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba --- fs/btrfs/file-item.c | 33 +++++++++------------------------ 1 file changed, 9 insertions(+), 24 deletions(-) diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index 9df9b91..1ce306c 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -350,10 +350,9 @@ blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio) const u32 csum_size = fs_info->csum_size; u32 orig_len = bio->bi_iter.bi_size; u64 orig_disk_bytenr = bio->bi_iter.bi_sector << SECTOR_SHIFT; - u64 cur_disk_bytenr; const unsigned int nblocks = orig_len >> fs_info->sectorsize_bits; - int count = 0; blk_status_t ret = BLK_STS_OK; + u32 bio_offset = 0; if ((inode->flags & BTRFS_INODE_NODATASUM) || test_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state)) @@ -404,28 +403,14 @@ blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio) path->skip_locking = 1; } - for (cur_disk_bytenr = orig_disk_bytenr; - cur_disk_bytenr < orig_disk_bytenr + orig_len; - cur_disk_bytenr += (count * sectorsize)) { - u64 search_len = orig_disk_bytenr + orig_len - cur_disk_bytenr; - unsigned int sector_offset; - u8 *csum_dst; - - /* - * Although both cur_disk_bytenr and orig_disk_bytenr is u64, - * we're calculating the offset to the bio start. - * - * Bio size is limited to UINT_MAX, thus unsigned int is large - * enough to contain the raw result, not to mention the right - * shifted result. - */ - ASSERT(cur_disk_bytenr - orig_disk_bytenr < UINT_MAX); - sector_offset = (cur_disk_bytenr - orig_disk_bytenr) >> - fs_info->sectorsize_bits; - csum_dst = bbio->csum + sector_offset * csum_size; + while (bio_offset < orig_len) { + int count; + u64 cur_disk_bytenr = orig_disk_bytenr + bio_offset; + u8 *csum_dst = bbio->csum + + (bio_offset >> fs_info->sectorsize_bits) * csum_size; count = search_csum_tree(fs_info, path, cur_disk_bytenr, - search_len, csum_dst); + orig_len - bio_offset, csum_dst); if (count < 0) { ret = errno_to_blk_status(count); if (bbio->csum != bbio->csum_inline) @@ -450,8 +435,7 @@ blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio) if (inode->root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID) { - u64 file_offset = bbio->file_offset + - cur_disk_bytenr - orig_disk_bytenr; + u64 file_offset = bbio->file_offset + bio_offset; set_extent_bits(&inode->io_tree, file_offset, file_offset + sectorsize - 1, @@ -462,6 +446,7 @@ blk_status_t btrfs_lookup_bio_sums(struct btrfs_bio *bbio) cur_disk_bytenr, cur_disk_bytenr + sectorsize); } } + bio_offset += count * sectorsize; } btrfs_free_path(path); -- 2.7.4